No abstract

Nowadays, coal production increases continuously due to an increase in mechanization in coal mining and demand in its related fields of application worldwide. Coal production in China is especially an increasing trend and a large amount of waste fine coal is produced. Waste fine coals usually contain large amounts of ash and inorganic sulfur due to non-selective coal mining of the coal. Therefore, waste fine coals are available as a resource and cause spontaneous combustion leading in turn to air pollution because of their coal contents and small particle sizes which increases the surface area liable to be wet and oxidized, and the disposal site of waste fine coals cause land occupation, soil pollution and water contamination.In this study, a vegetable oil agglomeration process was performed for coal recovery from Chongqing Nantong waste fine coals in China. The oil agglomeration process has been used to mineral oil of exhaustible resource. Therefore, in this study, several kinds of vegetable oils are selected as oil agglutinative agents because the vegetable oils which are renewable, available and less-pollutant energy resources. The effects of the parameters including particle sizes, agitation conditions, chemical structure and viscosity of vegetable oils were investigated based on the combustible matter recovery, ash reduction and efficiency index. It was concluded that particle sizes of waste fine coal, agitation rate and agitation time will influence on the recovery efficiency of combustible matter from its original waste coal by the colza oil agglomeration. Furthermore, a wide range of vegetable oil alteration grades including prepared waste vegetable oil samples and therefore, of oil properties, such as chemical structural changes and unsaturated carbonaceous functional groups by the oxidation processes in the used waste vegetable oils have to be achieved.

Coal production increases continuously due to the development of mechanization in coal mining and demand in its related fields of application worldwide. Especially, coal production in China is increasing and a large amount of waste fine coals (<0.5 mm) which are difficult to be cleaned. Waste fine coals usually contain large amounts of ash contents and inorganic sulfur contents due to the mechanical coal mining of low grade coals. Therefore, waste fine coals are unavailable as energy resources, spontaneous combustion leading in turn to air pollution because of their coal content and small size which increases the surface area liable to be wet and oxidized, and occupation of disposal land which is also lead soil and water contamination.In this study, a waste vegetable oil agglomerating process was approached for coal combustible matter recovery from Chongqing Nantong waste fine coals in China. The oil agglomerating process had usually been developed by mineral oil (such as kerosene) of exhaustible resource. Therefore, in this study, simulated waste vegetable oils are selected as oil agglutinative agents because the waste vegetable oils which are recycled, renewable, and less polluting energy resources from the point of view of effective utilization of waste coal and on the cost front. However, waste vegetable oils have the possibility of influence on the coal cleaning efficiency, because the waste vegetable oils may be changed in the surface property and viscosity by different kinds of vegetable oils and chemical structure with the usage environment. Therefore, in the study, cleaning coal efficiency of oil agglomeration was investigated when simulated waste vegetable oil (heating of colza oil) was used as an agglutinative agent. The effects of parameters including the viscosity and chemical structure were investigated based on the combustible matter recovery, ash reduction and efficiency index. Furthermore, combustion characteristics of combustible matter were determined with ignition temperature and burning behavior by TG-DTA. It can be concluded that the viscosity, types of vegetable oils, heating time and frying time of waste vegetable oils with the usage environment will influence the coal cleaning efficiency.

There are large quantities of waste rice husk, e.g. around 3 million tons are estimated as biomass waste every year in Japan. Air pollutants emitted from exhaust gases of rice husk incineration lead to very important environmental damage, not only because of the influence on global environment and climate, when released into the atmosphere, but also on human health due to local air pollution. Therefore, it is necessary to effectively utilize waste rice husk and to reduce air pollutants. In recent years, there is an increasing demand on the utilization of unused biomass instead of fossil oil fuel in combustors for farminggreenhouses heating during the winter season. This increase in the demand will increase the running costs. In general, since these combustors are small in size, there is lack of regulations or laws (e.g. the air pollution control act and the waste disposal and public cleaning law) in operation for their air pollution control. So far, small size combustors are characterized by their simplicity of structure and the low costs; therefore, they emit visible black carbon (elemental carbon) due to their poor combustion performance.In this study, we investigated if fossil fuel can be substituted by waste rice husk in laboratory model combustion experiments. We evaluated the emission behavior of harmful air pollutants emitted from rice husk combustion by measuring carbonaceous and ionic composition of suspended particulate matter in the exhaust gases. From the analytical results we found that particulate mass concentrations can be reduced substantially at high temperature combustion. Air Pollution XX 365constituted by Na + , K + , Ca 2+ , Cl -, NO 3 -and SO 4 2-which are easily vaporized, followed by homogeneous nucleation and heterogeneous condensation of these inorganic vapors. As the results of our study, it can be suggested that we have to ensure stable combustion performance under suitable conditions in order to control less air pollutants emitted from biomass fuel although small size combustors are still not regulated.

There are large quantities of rice husk estimated around 3 million tons as agricultural waste every year in Japan. Air pollutants emitted from exhaust gases of rice husk incineration lead to very important environmental damage, not only because of the influence on global environment and climate, when released into the atmosphere, but also on human health due to the local air pollution. Therefore, it is necessary to effectively utilize the rice husk waste and to reduce the air pollution. We try to develop a new-type air vortex current small-scale combustor which can effectively combust rice husk as biomass energy instead of fossil oil fuel for farming-greenhouses heating during the winter season. In this study, we investigated if rice husk can be fed on the new-type air vortex current small-scale combustor and reduced fossil fuel. The new-type small-scale combustor is able to keep a constant high temperature (about 1000°C) even if the rice husk combustion is not under the best conditions.At the same time, it is also important to evaluate the emission behavior of harmful air pollutants emitted from the rice husk combustion with measuring carbonaceous and ionic composition of suspended particulate matter (SPM) in the exhaust gases from the new-type air vortex current combustor, and to reduce the pollutant emission by controlling the combustion conditions. From the analytical results of the size distribution of carbonaceous composition collected by an air sampler, it is shown that elemental carbon dominated in the coarse particles, which are produced by incomplete combustion, and organic carbon dominated in the fine particles. Carbonaceous concentrations can be reduced substantially in the emitted particles by highly effective combustion when the combustor was improved. As the results of the ionic composition, high concentrations of potassium ion as a tracer of biomass burning were determined. Combustion temperature control is important to avoid corrosion in the system and the health effects from high concentrations of chloride contents.Although the new-type air vortex current combustor developed in our purpose is typically small-scale, however, usual fixed-bed combustors are prone to be incomplete because of the simplicity of the structure. Since there are no specific regulations for these kinds of combustors in Japan, therefore, even small combustor fall out of the possibly applicable emissions regulations, to ensure stable combustion performance and less air pollutants. In near future, we try to improve the combustor fed with less fossil oil fuel and more rice husk waste which will be feasible and sustainable.